Equipment for soft-coal-bttrning furnaces



June 5, 1928. 1,672,792

F. E. THOMES EQUIPMENT FOR SOFT COAL BURNING FURNACES Filed Oct. 11, 1926 Invenlan 25 to the fuel space inthe furnace.

.35 erenoe identify similar '1 tion of the grate and damper Patented June 5, 1928.

UNITED STATES FRANK E. THOMES, 01] SOUTH PORTLAND, MAINE EQUIPMENT FOR SOFT-COAL-BURNING FURNACES.

Application filed October 11, 1926. Serial No. 140,897.

My invention relates in a general way to furnace grates, but more especially has to do with a type of grate adapted for use in burning bituminous coal and coke.

5 A specific object of my resent invention is to provide better facilitles for unloading the grate when it becomes necessary to dump the fire; and for this pur ose I partially withdraw the grate proper fiom its supporting member soyas to allow a free, unobstructed passage way from the fuel space in the furnace to the ash-pit, for clinkers, ashes or any foreign matter in the coal.

Another object is to supply draft-con- .15 trolling. means in connection with and in close proximity to the rate itself, the purpose of which I will fiilly explain hereinafter in my specification.

Another important object is to reducethe ,20 grate area to. such an extent that it embraces only a portion of the full area of the fuelbed,--the remaining'surface which is ordinarily utilized-for grate purposes being closed to admission of air from the ash-pit I have a definitereason for thus decreasing the grate surface and this I will make known later on in the description of my apparatus. .Inthespecification following, l have dis closed one embodiment, which, at the present time, I consider preferable to other possible forms of the invention; and in the drawings accompanying and made a part of this applicatlon and in which like characters of refparts throughout all the different views, i i g Fig. 1 is a fragmentary front sectional elevation of a boiler and base member show- .ing my grate and grate carrier, also in sectional View;

, Fig. 2is similar to Fig. 1 except that the parts are shown in side sectional elevations;

or on line 2-2, 1; i

. Fig. 3 is a plan of the grate, viewed from line 3-3, Fig. 1; i

Fig. 4 is'a sectional plan taken 'on line 4-4, Fig. 2, the grate elements not being shown. i i i Fig. 5 is afragmentary enlarged cross sec-- slide, taken on line 22, Fig. 1; i y

Referring to Figs. 1 and 2, lrepresents thelower portion or the water leg of a boiler, 2; the base enclosing the ash-pit 3,

and .3 the ash-pit door.

Suspended from the top flange 2 of the base .is a fire-pot 4, preferably made in two parts, with the flange 4 thereof resting onv the-base flange 2'.

The body portion of the grate-carrier is cylindrical in form and depends into the ash-pit for a considerable distance. At its lower end it is provided with facilities for slidable mounting a. grate member 5 in grooves 6, and directly beneath and contiguous to this grate member is slidably mounted another grate element? operable in the grooves 8.

In grate 7 I provide 0 enings 7 which match the openings 5 in the grate 5. Both members, 5 and 7, have extended portions 5 and 7 respectively, and on these extensions are projections 9 and 10 by which the two grate elements, singly or collectively, may be operated backwardly or forwardly along their respective grooves, using for this purpose a poker or bent rod which is inserted in the holes in the projections.

At spaced intervals around the cylindrical body of the grate carrier 4 and formed in the wall thereof, are vertical slots 11, and mounted, preferably, on the outer periphery of the carrier is a cylindrical sleevc 12, the latter havingslots l3-which register with the slots 11 in the carrier 4. This sleeve is oscillat able on the body of the carrier so that the slots 11 may alternately be open and closed.

A handle 14 serves as means by which to oscillate the sleeve.

' The structural features of my device having been set forth, I will describe its operation after first pointing out a few facts concerning the ordinarily accepted method of operating soft coal fires on conventional. type grates.

First: The grate, as usually constructed extends over substantially the whole area of the fire-bed and air is permitted to penetrate the fuel over practically the whole surface of the grate. A certain amount of air is, of course, necessary to establish and maintain proper combustion of the fuel, but a matter which has apparently escaped the attention of engineers and inventors is the waste of heat units incurred by allowing the cool, or but slightly warm air from the ash pit to come into direct contact with the inside shell of the water-leg of the boiler. This air absolutely lowers the temperature of the boiler water and is therefore acting to defeat the purpose for which the fuel is being burned." v

In contrast to this, I bar the admission of air from the ash-pit to the fuel space at the marginal portions of the furnace by the interposition of the annular shaped flange 4 which extends completely therearound. And to further insure against pos sible air leaks at this point I make this flange serve as a seat or repository for ashes, represented in-Figs. 1 and 2 by the character a, and this assists in sealing the partition between the ash-pitand fuel space in the furnace at the lower marginal portion thereof.

.Second: The ash-nit door for heatingboilers will seldom be found completely closing the ash-pit to the entrance of air,the door joint never-being a tight fit, and, given a strong chimney draft, certain expedien'ts must be resorted to to provide the'proper check to the combustion of the fuel when the fire, is to be run low or smouldering. Flue or funnel openings to the outsideair and slides in the feed door are, the usual forms for this service. But openings throi'igh the feed door tend to cool the boiler water and there is therefore a distinct loss of heat units.

My method of draft control contemplates providing supplemental means apart from the usual devices employed for this purpose and consists in general of sealing, more 'or less completely, the under side of the fuelbed so asto prevent or control air communication between the fuel space and the space in the ash-pit. 1

The grate area in my device is decreased. to a large extent from what is ordinary practice. I do this because by thus contracting the size together with placing the grate centrally of the furnace all air pass ing into the fuel must first come in contact with the hottest portion thereof, and so when this air finally reaches the walls of the furnace it is hot air instead of cold. Better combustion also takes place when} the air mixingfwith the gases is hot, and verylittl'e smoke passes up the chimney. The operation of the grate may beaccom- .plished by a slight reciprocationof the grate "5, backwardly and forwardly, which will clear the top of the grate of the fine ash coal is to coke or solidify into a practically homogeneous mass after being slightly heated or burned. This mass remains intact, suspended as it were, in the furnace by. contact with its walls, so that this up or portion of the fuel-bed does not drop w en thegrate is removed to allow the ashes and clinkers to fall; and, after returning the grate to its working position, this top porconditions the air capacity through the grate is sufficient.

The invention chiefly consists in the three features,first, the adaptability of the device to seal the lower, marginal ortions of the furnace adjacent the water lisp; against the cooling effect of low temperature air, which, in ordinary furnaces rises" from "the ash-pit and impinges on theinnerwalls of the furnace; second, the provision made,

and employed when necessary, to air-seal the grate in close proximity theretmand third, the ability to completel withdrawthe twograteelenients to provie an open and unobstructed passage-way from the furnace space to the ash-pit for 'dumpingthe fire.

' Having thus described my invention, what I I claim isi 1. In equipment for soft-coal-burningfurnaces, comprising in combination a furnace base member having an openin in the top thereof, a hollow upright men 91' centrally disposed within said opening and having a plurality of aperturesin the wall thereof, a horizontal flange extendin outwardly from and around the wall 0. said.,.hollow member and adapted to rest on the top of said base member, a frame subtended from said hollowmember having a slide-way on each inner side thereof, a perforate'gmte element reciprocable in said slide-way and means to' co'rnpletely withdraw said grate element from said frame.

2. In equipment for soft-coal-burning furnaces, comprising'in combination a furnace base member having an opening in the top thereof, a hollow member centrall located in said opening, the axis thereof being vertical, an outwardly extending flange on the upper end of said hollow" member, said flange bearing on and supported'by the top of said base member, upstanding ports in the wall of said hollow member-,9. frame depending from said 'hollow'memben'two perforate ,qrate elementsfop'erable in said frame, one

elementabove the other, andmeans whereby either ofthe said grate elements may be reciprocated in said frame independently of the other.

3. In equipment for soft-coal-hurning furnaces, comprising in combination, a furnace base member having an opening in its top, a hollow member having open ends located within said base member and having an outwardly extending circumferential flange bearing on the top of said base member, said hollow member having through its wall a plurality of upstanding, relatively long and narrow apertures, closing means for said apertures, said means acting in a direction transversely of said apertures, a frame subtended from said hollow member and having on the inner sides thereof two vertically spaced slide-ways, a perforate grate element operable in each of said slide-ways and in adjacent vertical relation, relatively, and means to reciprocate said grate elements in said slide-ways, said reeiprocations effective to move said grate elements either singly or collectively.

4. In equipment for soft-coal-burning turnaces, comprising in combination, a furnace supporting member having an opening in the top thereof of relatively smaller diameter than that of the furnace, a long, upright cylinder disposed within said opening and depending for its full length into the space in said furnace-supporting member and having on its upper end a circumferential flange lying superjacent the top of said furnacesupporting member, a plurality of long, narrow ports in the wall of said cylinder and extending substantially the full length there of, a sleeve completely surrounding the said cylinder and having ports therein to match thosein said cylinder, means to oscillate said sleeve, a frame on the lower end of said. cylinder, two vertically spaced slide-ways in said frame, a perforate grate element operable in each of said slide-ways, means to actuate said grate elements whereby either one, in coaction with the other, may be made to fully close or to partially uncover the perforations in the other, and means to slid ably and completely withdraw either one or both of the two said grate elements from said frame.

Signed at Portland, county of Cumberland and State of Maine, this 8th day of June, 1927.

FRANK E. THOMES. 

